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Add CRC checking for nzb downloader example
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@mscdex
mscdex committed Apr 16, 2011
1 parent 512ecc3 commit 5d80003
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Showing 3 changed files with 109 additions and 37 deletions.
27 changes: 19 additions & 8 deletions examples/nzb/lib/nzb-worker.js
View file
Expand Up @@ -16,16 +16,16 @@ function postError(e) {
postMessage({ event: 'error', err: e });
}

function decodeArticles(ids, index, filename) {
function decodeArticles(ids, index, path, filename) {
index = index || 0;
postMessage({ event: 'decode', part: index+1, total: ids.length });
var path;
if (index === 0) {
path = pathComplete + Date.now();
fs.mkdirSync(path, '0777');
path += '/';
}
var stream = ydec(fs.createReadStream(pathTemp + ids[index]));
var stream = ydec(fs.createReadStream(pathTemp + ids[index])),
corrupt = false;
stream.on('data', function(data) {
out.write(data);
});
Expand All @@ -35,13 +35,24 @@ function decodeArticles(ids, index, filename) {
out = fs.createWriteStream(path + filename);
});
}
stream.on('yend', function(yend) {
if (!yend.crcMatches)
corrupt = true;
});
stream.on('end', function() {
fs.unlink(pathTemp + ids[index]);
if (++index < ids.length)
process.nextTick(function() { decodeArticles(ids, index, filename); });
else {
if (!corrupt) {
fs.unlink(pathTemp + ids[index]);
if (++index < ids.length)
process.nextTick(function() { decodeArticles(ids, index, path, filename); });
else {
out.end();
postMessage({ event: 'done', filename: filename });
}
} else {
out.end();
postMessage({ event: 'done', filename: filename });
fs.unlink(path + filename);
fs.renameSync(pathTemp + ids[index], pathTemp + 'corrupt_' + ids[index]);
postMessage({ event: 'done', filename: filename, corrupt: true });
}
});
}
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111 changes: 84 additions & 27 deletions examples/nzb/lib/ydec.js
View file
Expand Up @@ -7,27 +7,79 @@ var CRLF = [13, 10],
yEnd = [0x3d, 0x79, 0x65, 0x6e, 0x64, 0x20],
yPart = [0x3d, 0x79, 0x70, 0x61, 0x72, 0x74, 0x20];

function decode(data) {
var newBytes = new Array(), escaped = false;
var crc_tab = [
0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
];

function decode(data, crc) {
var newBytes = new Array(), escaped = false, val;
for (var i=0,len=data.length; i<len; ++i) {
if (data[i] === 61) {
// TODO: make sure '=' isn't the last char!
escaped = true;
} else {
if (escaped) {
newBytes.push(data[i] - 106);
val = data[i] - 106;
escaped = false;
} else
newBytes.push(data[i] - 42);
val = data[i] - 42;
newBytes.push(val);

// CRC update
crc.val = (crc.val >>> 8) ^ (crc_tab[(crc.val ^ val) & 0xff]);
}
}
return new Buffer(newBytes);
}

module.exports = function(instream) {
var crc = { val: -1 };
var outstream = new Stream(), state = 'pre', buffy = new Buffy();
var meta = {
begin: {
part: undefined,
size: undefined,
total: undefined,
line: undefined,
Expand All @@ -41,7 +93,8 @@ module.exports = function(instream) {
size: undefined,
part: undefined,
pcrc32: undefined,
crc32: undefined
crc32: undefined,
crcMatches: undefined
}
}, eolPos, startPos = 0, hasProcessed = false, line, r;
instream.on('data', function(data) {
Expand All @@ -52,7 +105,6 @@ module.exports = function(instream) {
startPos -= r;
eolPos -= r;
}
hasProcessed = true;
if (eolPos - startPos > 0) {
line = new Buffer(eolPos - startPos);
buffy.copy(line, 0, startPos, eolPos);
Expand All @@ -64,50 +116,55 @@ module.exports = function(instream) {
meta.begin[kv[0]] = parseInt(kv[1], 10);
});
meta.begin.name = result[2];
state = 'checkpart';
if (typeof meta.begin.part !== 'undefined')
state = 'part';
else
state = 'data';
outstream.emit('ybegin', meta.begin);
}
} else if (state === 'checkpart') {
} else if (state === 'part') {
state = 'data';
var isHeader = false;
if (line.startsWith(yPart)) {
var result = line.toString().match(/^=ypart (.+?)$/);
if (result) {
result[1].split(' ').forEach(function(s) {
var kv = s.split('=');
meta.part[kv[0]] = parseInt(kv[1], 10);
});
isHeader = true;
outstream.emit('ypart', meta.part);
}
}
if (!isHeader)
outstream.emit('data', decode(line));
var result = line.toString().match(/^=ypart (.+)$/);
result[1].split(' ').forEach(function(s) {
var kv = s.split('=');
meta.part[kv[0]] = parseInt(kv[1], 10);
});
outstream.emit('ypart', meta.part);
} else if (state === 'data') {
var isHeader = false;
if (line.startsWith(yEnd)) {
var result = line.toString().match(/^=yend (.+?)$/);
var result = line.toString().match(/^=yend (.+)$/);
if (result) {
result[1].split(' ').forEach(function(s) {
var kv = s.split('=');
meta.end[kv[0]] = (kv[0] === 'part' || kv[0] === 'size'
? parseInt(kv[1], 10) : kv[1]);
});
var ycrc = undefined;
if (typeof meta.end.pcrc32 !== 'undefined')
ycrc = parseInt(meta.end.pcrc32, 16);
else if (typeof meta.end.crc32 !== 'undefined')
ycrc = parseInt(meta.end.crc32, 16);
crc.val = crc.val ^ (-1);
if (crc.val < 0)
crc.val += 0xFFFFFFFF + 1;
if (typeof ycrc !== 'undefined')
meta.end.crcMatches = (crc.val === ycrc);
else
meta.end.crcMatches = undefined;
state = 'pre';
crc.val = -1;
isHeader = true;
outstream.emit('yend', meta.end);
}
}
if (!isHeader)
outstream.emit('data', decode(line));
outstream.emit('data', decode(line, crc));
}
line = undefined;
}
startPos = eolPos + 2;
}
if (hasProcessed) {
hasProcessed = false;
}
});
instream.on('end', function() {
// need to check if =yend is still in our buffered data, in case there was
Expand Down
8 changes: 6 additions & 2 deletions examples/nzb/nzb.js
View file
Expand Up @@ -69,8 +69,12 @@ else {
console.log('Main :: Worker #' + wnum + ' is decoding part '
+ m.data.part + '/' + m.data.total + ' ...');
} else if (m.data.event === 'done') {
console.log('Main :: Worker #' + wnum + ' finished downloading file: '
+ m.data.filename);
if (m.data.corrupt)
console.log('Main :: Worker #' + wnum
+ ' detected a corrupt part, part filename marked ...');
else
console.log('Main :: Worker #' + wnum + ' finished file: '
+ m.data.filename);
if (nzb.file.length) {
var m = { config: config };
if (user || pass)
Expand Down

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